Organic Light-Emitting Diodes (OLEDs) are promising in the display technical field due to the advantages thereof. However, active metals for forming a metal cathode in the OLED device are very sensitive to vapor and oxygen in air, and are very easy to react with the vapor that has been permeated, to affect injection of a charge. In addition, vapor and oxygen that are permeated also react chemically with organic materials. These reactions are primary factors that cause performance degradation of the OLED device and shorten service life of the OLED device. Therefore, packaging technology is very important for OLED devices.